Sex, age, and parental harmonic convergence behavior affect the immune performance of Aedes aegypti offspring

Abstract

Harmonic convergence is a potential cue, female mosquitoes use to choose male mates. However, very little is known about the benefits this choice confers to offspring performance. Using Aedes aegypti (an important vector of human disease), we investigated whether offspring of converging parental pairs showed differences in immune competence compared to offspring derived from non-converging parental pairs. Here we show that harmonic convergence, along with several other interacting factors (sex, age, reproductive, and physiological status), significantly shaped offspring immune responses (melanization and response to a bacterial challenge). Harmonic convergence had a stronger effect on the immune response of male offspring than on female offspring. Further, female offspring from converging parental pairs disseminated dengue virus more quickly than offspring derived from non-converging parental pairs. Our results provide insight into a wide range of selective pressures shaping mosquito immune function and could have important implications for disease transmission and control.

Sexual selection theory meets disease vector control: Testing harmonic convergence as a “good genes” signal in Aedes aegypti mosquitoes

“…Our data do not support a good genes model of indirect sexual selection for the fitness traits examined here. Previous studies have observed correlations between parental harmonic convergence and both offspring immunity [40] and mating success [19], consistent with good genes and Fisherian selection models, respectively. We therefore propose that sexual selection likely affects Ae.…”

“…For these measures to succeed, it is critical that modified mosquitoes successfully compete with their wild counterparts for mates. Although harmonic convergence can serve as a helpful readout of mating success [ 19 , 20 , 28 ] and at least some measures of inherent quality [ 40 ], our results suggest that harmonic convergence is not a reliable indicator of all aspects of overall mosquito quality and that the relationship between some parental and offspring fitness measures is not easily predictable. Hence, care should be exercised when using harmonic convergence and the other fitness measures examined here to infer various aspects of modified mosquito strain quality relative to their natural counterparts [ 86 ].…”

“…Consistent with this, as well as our present findings, a meta-analysis of indirect benefits studies found that while offspring life history traits, such as the ones examined here, were not associated with father attractiveness, traits directly linked to paternal mating success were [ 76 ]. While we did measure a performance trait here (i.e., flight performance), most studies that have documented associations between offspring performance and father attractiveness were related to immunocompetence [ 40 ] and physical condition, for example as expressed in weight at maturity [ 76 ]. Future studies could further investigate these selection models and the extent of their applicability by assaying additional traits, conducting detailed pedigree analyses in various mosquito lines, or varying environmental conditions.…”

“…In support of good genes models, a recent study in Ae . aegypti showed that parental harmonic convergence correlates with aspects of offspring immune performance [ 40 ]. Consistent with Fisherian predictions, another study in Ae .…”

Harmonic convergence coordinates swarm mating by enhancing mate detection in the malaria mosquito Anopheles gambiae

“…coluzzii 42 , 43 ). As harmonic convergence also correlates strongly with mating success 29 , 44 , 45 , studies on sexual selection and mate preference suggest that convergence may be used in courtship to signal some 30 , 46 , but not all 47 aspects of mosquito fitness . Despite these discoveries, much of the previous work on harmonic convergence has examined tethered, rather than free-flying males and females.…”